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LYU9903 QoS Schemes in Wireless Networks

LYU9903 QoS Schemes in Wireless Networks. Ho Pun Mo & Ng Maggie Supervised by Prof. Lyu R.T. Michael 6 December, 1999. Outline. Introduction Wireless Networks QoS Performance Evaluation QoS in Wireless Networks Application - Video Future Work. Introduction.

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LYU9903 QoS Schemes in Wireless Networks

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  1. LYU9903QoS Schemes in Wireless Networks Ho Pun Mo & Ng Maggie Supervised by Prof. Lyu R.T. Michael 6 December, 1999

  2. Outline • Introduction • Wireless Networks • QoS • Performance Evaluation • QoS in Wireless Networks • Application - Video • Future Work

  3. Introduction • Concern about QoS and wireless networks • QoS is not as simple as one would think • Platform we choose is Linux • Focus on: • investigating and analyzing QoS schemes on wireless networks • measuring and comparing performance on wired/wireless networks

  4. Wireless Networks • Wireless Local Area Networks (Wireless LANs) • Wireless Wide Area Networks (Wireless WANs)

  5. Wireless LANs • Extension to /Alternative for Wired Network • IEEE 802.11 standard • Using Radio Frequency (RF) • connected as infrastructure network

  6. Wireless LANs What is Infrastructure Network?

  7. Wired vs Wireless Networks • different physical & datalink protocols • different hardware • wireless networks: Roaming • different performance

  8. Why Wireless? • Importance of Wireless LANs: • increasing of mobility • Trend of Wireless LANs: • better performance • lower cost

  9. Why Wireless? • Applications of Wireless LANs: • in hospitals • in campus • in retail stores & restaurants • in warehouses • in old buildings

  10. WaveLAN WavePOINT-II Access Point Proxim RangeLAN2 Ethernet & Token Ring Access Point Wireless Devices • Access Points:

  11. Wireless Devices • PC Cards: WaveLAN Turbo(Bronze) PC Card Proxim RangeLAN2 7400 PC Card • Date Rate: 2-6 Mbps • Range: 40-115m (indoor) 120-540m (outdoor) • Freq.: 2400-2483.5MHz • Date Rate: 1.6 Mbps • Range: 152m (indoor) 305m (outdoor) • Freq.: 2.4GHz

  12. Pros & Cons of Wireless • Advantages: • Mobility • Flexibility • Ease of Installation • Cost of Installation • Security • Enough Bandwidth for Office Uses

  13. Pros & Cons of Wireless • Disadvantages: • Low Bandwidth • High Error Rates & High Delay • Limited Range of Coverage • Large Consumption of Battery • Unwanted Interference

  14. What is QoS? • There are many QoS’s • We concern about QoS in computer networks • Some definitions: • the collective effect of service performances which determine the degree of satisfaction of a user of the service • the ability of a network to deliver time-bounded traffic types (e.g. real time video or voice) with predictable latencies • a way to specify an applications network performance requirements, and it is specified by performance parameters

  15. What is QoS? • What QoS means to us: QoS is the guarantee of delivering network packets punctually and the guarantee of delivering an acceptable numbers of network packets in a compromised time interval, which would not annoy the receivers.

  16. Why QoS? • Statistic from Cisco shows that multimedia applications become more and more popular

  17. Why QoS? • Which one do you prefer? Normal Long Delay Lost Frame

  18. How to Achieve QoS? • Many ways Bandwidth reservation + Packet scheduling • Bandwidth reservationRSVP • Packet schedulingCBQ

  19. How to Achieve QoS? ~ Bandwidth Reservation • RSVP is a protocol that allows channels or paths on the networks to be reserved for the transmission of video and other high-bandwidth messages.

  20. How to Achieve QoS? ~ RSVP

  21. How to Achieve QoS? ~ Packet Scheduling • There are many packet scheduling algorithms • Some examples: • FIFO - First In First Out • SFQ - Stochastic Fairness Queuing • WFQ - Weighted Fair Queuing • CBQ - Class Based Queuing • Focus on CBQ

  22. How to Achieve QoS? ~ CBQ • Hierarchical link-sharing structure

  23. Server     Client Architecture ~ Combining RSVP and CBQ

  24. Application: FTP Server Client Application: MP3 player Ethernet Performance Evaluation ~ Wired Networks • Scenario:

  25. Performance Evaluation ~ Wired Networks • Results with & without QoS

  26. noqos qos Performance Evaluation ~ Wired Networks • Applied QoS & NoQoS in same experiment

  27. Performance Evaluation ~ Wired Networks • What can you see from the results? • QoS makes MP3 playing smoothly • QoS benefits both MP3 and FTP applications • QoS can be applied on the fly

  28. Application: FTP Client Application: MP3 player Server Access Point Ethernet Performance Evaluation ~ Wireless Networks • Scenario:

  29. Performance Evaluation ~ Wireless Networks • Performance on using the Proxim devices

  30. Performance Evaluation ~ Wireless Networks • Performance on using the WaveLAN devices

  31. noqos qos noqos qos Performance Evaluation ~ Wireless Networks • With / without QoS in the same experiment Received Bandwidth of FTP & MP3 with 200Kbits (using Proxim) Received Bandwidth of FTP & MP3 with 200Kbits (using WaveLAN)

  32. Performance Evaluation ~ Wireless Networks • What can you see from the results? • QoS makes MP3 playing smoothly • QoS benefits both MP3 and FTP applications • Wired Networks vs Wireless Networks:Wireless Networks have larger delay • Proxim vs WaveLAN:seems Proxim performs better!

  33. QoS in Wireless Networks • Problems: • Variable bandwidth • Roaming • Low Reliability and Long Delay • Interference • Hard disk bottleneck • Solutions: • Renegotiation • Apply QoS in Access Points • Network Collision Control

  34. Application - Video • Real time video player for both wired and wireless networks with QoS enabled • Design: • RPC • Enabled QoS • Buffering at both client and server side • RAPI

  35. Future Work • Measure the delay jitter of the QoS systems (both wired and wireless) • Measure the performance of the QoS systems with router presented • Finish our video application with QoS enabled • Measure the performance of our video application • Inspect the source code of WaveLAN driver in order to make it QoS enabled

  36. The End Thanks!

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